The instruction and feature for double mould

There are two kinds of double mould : one is over mould , the other one is double mould .

There are two kinds of double mould :  one is over mould , the other one is double mould .
The over mould Is mean that injecting one part first , then telescope it to another mold and be to a new part .
Double color include independent double color and mix double color :  independent double color is mean that make two kinds of color on one machine , usually finish it by displacing the cover mold(by turning mold ), A double mold need make two sets of mold, the same two sets of cavity , and different two sets of cover,   two sets of mold base can be exchangeable ; Mix double color, just need one set of mold , need the special plastic machine, which is annex two piece of independent nozzle, and control the injection parameter of each nozzle independent .
Feature for double mould
a. Double mold need the matched injection machine 
b. There are one rotation gear or slide gear .
c. There are difference between cover mold, but the cavity is the same.
d. Attention to the cylinder or other dynamic application 
e. High requirement for precision